[signin] Add feature flag for mobile account consistency on Android

The CL adds the flag and plumbs it to the reconcilor.

A basic version of the Mice reconcilor is created. It is not functional
yet, but will be improved in future CLs.

Change-Id: I0df18ba41690db6c87d59ebcfa7f84a65bbbb7bc
Reviewed-on: https://chromium-review.googlesource.com/c/1475533
Reviewed-by: Elly Fong-Jones <[email protected]>
Reviewed-by: Boris Sazonov <[email protected]>
Commit-Queue: David Roger <[email protected]>
Cr-Commit-Position: refs/heads/master@{#634177}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index fd2c2fe..e0d7ee3 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -4202,6 +4202,10 @@
      flag_descriptions::kManualPasswordGenerationAndroidDescription, kOsAndroid,
      FEATURE_VALUE_TYPE(
          password_manager::features::kManualPasswordGenerationAndroid)},
+    {"mobile-identity-consistency",
+     flag_descriptions::kMobileIdentityConsistencyName,
+     flag_descriptions::kMobileIdentityConsistencyDescription, kOsAndroid,
+     FEATURE_VALUE_TYPE(signin::kMiceFeature)},
 #endif  // defined(OS_ANDROID)
 
     {"autofill-show-full-disclosure-label",